Secondary electric clock



(N0 Model.)

W. B. HARVEY.

SECONDARY ELECTRIC CLOCK.

Patented Mar. 29, 1887.

JI-Ill.

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ATTH/VEY N. PETERS. Pnowulhngmphnr, washington, D. C.

Anized every hour.

UNITED A STATES PATENT OEEICE.

VIRT B. HARVEY, OE MEMPHIS, TENNESSEE.

SECONDARY ELECTRIC CLOCK.

SPECIFICATION forming part of Letters Patent No. 360,092, dated March 29, 1887.

i Application filed December 7, 1885. Serial No. 185,019. (No model.)

To all whom it may concern..-

Be it known that I, WIRT B. HARVEY, a citizen of the United States, and a resident of Memphis, in the county of Shelby and State of Tennessee, have invented certain new and useful Improvements in Secondary Electric Clocks, described, claimed, and shown in the following specification, claims, and drawings.

My invention relates particularly to secondary electric clocks provided with synchronizing apparatus adapted to operate not only once an hour, but also every twelve hours, the same being accomplished by intermittent cur rents communicatedthereto by a transmitting signaling apparatus located at a central station. My. present invention does not relate to the transmitter, to the batteries, to the system of distributing the current, nor to apparatus for protecting the system from lightning or aecidental short-circuiting. It is confined en` tirely within the secondary electric clock itself.

Synehronizing properly means to set all the clocks in a system at exactly the same time, and in orderto accomplishthis a synehroniz ing apparatus is placed in each secondary electricclock. 'Ihissynchronizingis accomplished at twelve oclock at noon and at twelve oclock at night. Some of the clocks may lose time every hour, so that they need to be synchro These corrections are accomplished by a peculiarfapparatus located within the secondary electric clock, the force operating the same being an electric current dispatched from a central station.

There are various devices which I have inventedfor accomplishingthis compound synch- .ronizing' action, two of which form the subject-matter of my applications now pending in the Patent Office, No. 175,300, :tiled August 25, 1885, and N o. 183,171, tiled November 18, 1885. The former shows a secondary electric clock where the hands are operated by an electro-magnet and the synchronizer by a polarized relay, while in the latter both the synch` ronizer and the hands are each operated by a polarized relay. In this application it will be shownhow the hands and synchronizing apparatus are both operated by electromagnets under theiniiuence of currents of varying amount.

The object of the invention described in this application is to provide a secondary electric clock which will operate effectively under the influence of two currents, the one being a multiple of the other as regards strength, so that by means of one wire the different parts of the clock may be operated, one current serving to operate the hands during the space of cach hour, or thereabout, and the other current serving to operate the hands in such a manner as to move faster than usual for afew seconds, or even minutes, preferably at the end of one or more hours.

The instrument consists of the combination of two electro-magnets, two cut-outs, one operating at short intervals, preferably once an hour, and the other at long intervals, preferably once in twelve hours, and both serving to cut out the magnet responding to the current of smaller strength at the above-named intervals, and suitable ordinary clock-gearing and electrical connections.

In order to illustrate the practical manner of carrying out the invention, drawings are hereunto annexed and described, in which similar letters of reference represent corresponding elements, and in which each part referred to is designated by a single letter. Those parts not mentioned I do not claim in this my present application. The materials of construction employed, the exact forms of design, and the proportional dimensions are not alluded to, as they are best determined upon by those versed in the art.

Figure 1 represents the secondary electric 85 clock embodying myinvention, which consists ot the combination of numerous elements, the principal of which are the lninutehand A and hour-hand B; an operating device consisting of the electro-magnet C, the pivoted armature D,having a retractile spring, E, and a ratchet, F, attached to said armature; asynchronizer consisting ot' similar parts, named` respectively, C', D', E', and F, the spring E being more powerful than the hist-named re- 95 tractile spring E; a ratchet-wheel, G, for said ratchets, and fixed upon the shaft H of said minute-hand and having one tooth omitted, as at I; a cut-out, one contact, J, being fixed to the armature, and the other, K, being adjacent thereto, but having no rigid connection therewith, said cut-out when closed being in direct circuit with magnet C', a detent-wheel, I., upon the minute-hand shaft H; a second IOD one, M, upon the hour-hand shaft H; a cutout, N, geared to said detcnt-wheels through the bent lever O, and when closed in direct circuit with magnet C', and ordinary toothgearing, I), connecting the hour and minute y/hands The screw-heads shown at the extreme right of the drawingsindicate the poles of any electric generator, and are therefore designated in the usual manner by the plus and minus sign, H- and Some of the details of construction are as follows:

Fig. 2 shows a side view of the dctent-wheels and the cut-out geared thereto, the cut-out being somewhat modified, caused by placing a bent lever, O', in aplane parallel to the detent-wheels M and L. rIhe lines composed of alternate dots and dashes show the course of the current in so far as is necessary to the understanding of its action upon the various parts.

Once every minute an instantaneous current passes through the magnet C, which attracts the armature D and its ratchet F, the latter causing the wheel G to rotate in the well-known manner. In turn motion is communicated to the minute and hour hands of the clock and to the detent-wheels M and L. Once in twelve hours, it is evident from the nature of the description and from the wellknown relative motions of clock-hands and their shafts, the detents Q and Rin the wheels M and L come opposite each other, or in line with the lever, so that the lever O falls into both detents once every twelve hours, the above operation causing a closing of the cutout N, so that the main current passes through the magnet C alone, instead of through C and C. Consequently the ratchet F no longer operates, but is retained out of contact with the wheel G by means of the retractile spring E. Any other clock in the system has exactly the same construction, although such construction may not be of the same accuracy of workmanship. In addition to such inaccuracy, other causes contribute toward a retardation of the hands of some of the clocks, so that they do not indicate the saine time as the central standard time. Vhen the lever O drops into the detents Q, and R in any clock, that clock indicates twelve oclock, which may be either correct or incorrect. However, the hands remain quiet until a strong current sufficient to operate the ratchet F passes through magnet C. By a device which will form the subject matter of another application the standard clock at the central station is so constructed that this strong current passes through magnet C one or more times at exactly twelve oclock by the standard time. rIhe detents, therefore, moving, throw apart the contacts at N, so that the magnet C operates the hands as before, the current passing through magnet C being insufficient to operate the armature D.

At the end of each hour the clock corrects itself in the following manner: The space I is in such a position in relation to the ratchet F that at thefty-ninth minute of any hour no difference how many times the magnet C attracted the armature D, it could not move the wheel G after the ratchet F had fallen into the space I; so, then, if the clock is ahead of correct time when this happens, it will stop until the armature D operates, while if it is behind correct time the armature D will operate until it brings the space I past the ratchet F, the impulses through G being more rapid than through C. The said impulses are made by ordinary telegraplrkeys locatedin circuit with the magnets C and C. Such keys and their modes of operation may be seen, forinstance, in Frank L. Popes Modern Practice of the Electric Telegraph, page 2S. At exactly the even hour, by standard time, rapid impulses pass through the magnet C. Magnet C' operates the armature F rapidly, which rotates the wheel G forward until the hands A and B indicate standard time.

The invention is not limited to the precise construction hereinbefore described and shown, as it is evident that many modifications may be made therein without departing from the spirit ofthe invention. For instance, the cut-out device N may be replaced by its equivalent, such as shown in my other applications already referred to by date and number. The magnet that usually docs the printing in Edisons synchronizer, and the groove containing a catch well known, in use by the Gold and Stock rlelegraph Gompanys instrument, can replace the operating-magnet C. Other changes within the contines of the claims annexed may be made.

Having now stated the object of the said invention, having described its practical realization by reference tothe accompanyin g drawings, having particularly ascertained the manner in which the same operates to accomplish the said object, and having intimated that it is applicable to other purposes than those mentioned, what I consider to be novel and original, and therefore claim as my invention, and desire to have secured to me by the hereinbeforein-part-recited Letters Patent ofthe United States, is-

1. In a secondary electric clock, the combi nation of an operating device and a synchronizing device, each consisting of a magnet and its armature and a pawl upon each armature, one armature being provided with a weaker retractile spring and the other with a stronger retractile spring, and the two said devices having suitable electrical connections, and the two magnets being in a common circuit, substantially as described.

2. In a secondary electric clock, an automatic operating electrical device and an electrical synchronizing device, both being geared to a single ratchet-wheel upon the main shaft of said clock, substantially as and for the purpose described and illustrated.

3. In a secondary electric clock, the combination of an electrical operating device located in a weaker current, an electrical synchroniz- ICO IIO

IIS

ing device located in a stronger current, and a eut-out for said operating device having operating connection with said synchronizing device, the said operating and synchronizing device having operating connection with a ratchet-Wheel located upon the shaft of the minute-hand of said clock, substantially as and for the purpose described.

4. In a secondary electric clock, the combination of hour and minute hands, two electromagnetic operating devices having operating connection with saidhands, an electric cut-out having operating connection with said hands, both of said devices being in circuit when said cut-out is open, and only one of said devices being in ,circuit when the cut-out is closed,substantially as and for the purpose described.

5. In a secondary electric clock, the combination of a minute-hand, a ratchet-wheel upon the shaft of said minute-hand, pawls gearing into said wheel, armature attached to said pawls, electro-magnets to said armatures, and currents of unequal strength alternately passing through said magnets, substantially as and for the purposes set forth.

6. In a secondary electric clock, the combination of minute and hour hands, an operating device consisting of an electro -magnet, its armature and pawl and a ratchetwheel upon the shaft of said minute-hand and 3o having one tooth omitted, said armature being provided with a pawl which gears into said Wheel and having a weaker retractile spring, a synchronizing device consisting of the saine elements as the operating device, except that the retractile spring is more powerful under the same stress, a weaker current passing at shorter intervals through said operating device and a stronger current at longer intervals through said synchronizer, and electric cut- 4o out to said operating device and geared to said synchronizing device, detent-wheels upon the shafts of said minute and hour hands, and a A second electrical cut-out to said operating de vice geared to said detentwheels, substan- 45 tially as described, and for the purposes intimated.

In testimonywhereof I hereunto subscribe my name, in the presence of two subscribing Witnesses, this 23d day of November, A. D. 5o 1885.

VVIRT B. HARVEY.

Vitnesscs:

C. W. HALBERT, J E. FoosT. 

